Polynucleotide barcodes have utility in numerous applications, including next generation sequencing techniques. Such barcodes generally contain unique identifier sequences, which can be extremely expensive to manufacture at sufficient diversity and scale. The cost of synthesizing a single polynucleotide barcode is a function of the cost per base during synthesis and the length of the polynucleotide. The cost of synthesizing a plurality of barcodes, each with a different sequence, is therefore equivalent to the cost per base, multiplied by the number of bases per molecule, multiplied by the number of molecules within the plurality of barcodes. Currently, it costs approximately $0.10 per base to synthesize a DNA sequence. For a barcode library of tens of thousands to millions of barcodes, this cost is prohibitive. Thus, there is a significant need for improved methods of generating libraries of barcodes.